Amps drop on cross-country flight

[Paul_G]

I made my longest cross-country flight in my Sirius TL-3000 last week. Everything went fine until about 5 hours into the flight the amps dropped to 1 or 2 amps. It corrected itself after a minute or two and then did it again 2 or more times. It only lasted a total of 4 or 5 minutes and was then fine the remainder of the flight. The voltage dropped to about 11.9 during this event. I downloaded the data from my Dynon displays and uploaded them to SavvyAviaion.com to confirm what happened. Has anyone experienced this with the 912 ULS?

Thanks in advance for you comments.

[drseti]

How many hours on the engine? I've seen issues with mid-time voltage regulators that resemble this. It's usually not the regulator itself, but rather corrosion on the blade terminals. You could try removing the connector, cleaning up the blades, smoothing dielectric grease on them, and then replacing the connector. You should also check the quality of the ground connection between the regulator housing and the firewall.

[Paul_G]

The Rotax has 200 hours.

[drseti]

The Rotax has 200 hours.

That's kind of low time for regulator problems. Try checking all your system grounds for tightness and good electrical contact.

[ShawnM]

I've heard of them failing in as little as 200 hours, it all depends on how cool they are kept. That being said do as Paul suggested and clean, tighten (squeeze the terminals closed a little) and grease the connector and slip it back on. As for the grounding, it is best if you have a ground lead from the body of the regulator to the negative battery terminal. Relying on the "chassis" grounding only for the regulator is not best practice and can cause premature failures. I assume then that you don't have the warning light hooked up on the regulator? It will come on if the voltage regulator is not working. I have a bright red LED on my panel right in front of me that is illuminated when the voltage regulator is not working.

Here's a pic of mine after it's quarterly checkup, packed with dielectric grease about to be slipped back on the regulator. I have the Silent Hektik voltage regulator but I still treat it the same way, keep it as cool as possible and maintain a great connection with regular scheduled maintenance on the regulator connector and terminals.

connector with dielectric grease (Medium).jpeg (64.77 KiB) Viewed 2554 times

[Paul_G]

Thanks Shawn and Paul for the info. I'll get some dielectric grease and hope the problem never appears again.

[Warmi]

Since it is hard to determine if your modules and the regulator are being overheated, you may want to get a couple of adhesive temperature strips ( 160 F ) from Amazon and install them in strategic locations .... if you ever blow thru 160 F ( which is the temp at which , according to Rotax , damage may start occurring ) you will know right away ...

Strips.jpg (191.78 KiB) Viewed 2522 times

[fatsportpilot]

I've heard the Ducati voltage regulators Rotax uses are low quality. Is that still the case with modern Rotax engines?

[drseti]

All the current production Rotax 900 series engines still use the Ducati rectifier/regulator. Our own Fast Eddie successfully converted the 912ULS in his ELSA to a John Deere regulator.

[ShawnM]

As I mentioned in an earlier post I installed the Silent Hektik voltage regulator on my E-LSA SportCruiser years ago and it's far superior to the Ducati. There is a Thermax brand temp strip on the right side of it (not seen in the photo) that reads from 149° to 199° and I've never reached the 149° mark yet.

I think the John Deere and the Silent Hektik are the two most popular alternatives.

regulator and cap on firewall (Small).jpeg (90.69 KiB) Viewed 2455 times

[drseti]

Nice picture, Shawn. May I have your permission to use it in one of my PowerPoint presentations?

[Wm.Ince]

That's a nice installation, Shawn.

[ShawnM]

Nice picture, Shawn. May I have your permission to use it in one of my PowerPoint presentations?

Absolutely, if you need a higher rez pic let me know, I always resize my pics way down before I upload them to online forums.

That's a nice installation, Shawn.

Thanks Bill.

[fatsportpilot]

As I mentioned in an earlier post I installed the Silent Hektik voltage regulator on my E-LSA SportCruiser years ago and it's far superior to the Ducati. There is a Thermax brand temp strip on the right side of it (not seen in the photo) that reads from 149° to 199° and I've never reached the 149° mark yet.

I think the John Deere and the Silent Hektik are the two most popular alternatives.

regulator and cap on firewall (Small).jpeg

What makes it far superior anyway? Is it just more reliable at high temperatures?

[drseti]

What makes it far superior anyway? Is it just more reliable at high temperatures?

Greater heat sink area, I believe (which indeed leads to greater reliability at higher temperatures).